In order to spray a liquid, use is generally made of centrifugal pumps which are coupled to a thermal engine. The drawback of such pumps is that they require a relatively high power. For example, a centrifugal pump which has an output of 1300 liters/minute at a pressure of 12 bar requires, for the thermal engine in which drives this, a power of 120 continental horsepower.
The aim of the invention is to propose a liquid pumping system which considerably reduces this power required for spraying said liquid, for example in a ratio of 8 to 10.